In mid-October, there was a palpable sense that America was on the cusp of an Ebola outbreak: Thomas Eric Duncan, a Liberian man who flew to the Dallas area carrying the virus, had died, and two of the nurses who tended to him contracted Ebola in the process.There were at least 70 other potential cases at Texas Health Presbyterian Hospital Dallas alone, plus the people Duncan came in contact with and those who interacted with nurses Nina Pham and Amber Vinson, the latter of whom flew on passenger jets to and from Ohio.By late last week, other nurses at the hospital and the national nurse's...